The present invention relates in general to process control for reproduction apparatus, and more particularly to modification of process control signals so as to enable reproduction apparatus to operate over an alternate process range.
In typical commercial electrostatographic reproduction apparatus (copier/duplicators, printers, or the like), a latent image charge pattern is formed on a uniformly charged charge-retentive or photo-conductive member having dielectric characteristics (hereinafter referred to as the dielectric support member). Pigmented marking particles are attracted to the latent image charge pattern to develop such image on the dielectric support member. A receiver member, such as a sheet of paper, transparency or other medium, is then brought into contact with the dielectric support member, and an electric field applied to transfer the marking particle developed image to the receiver member from the dielectric support member. After transfer, the receiver member bearing the transferred image is transported away from the dielectric support member, and the image is fixed (fused) to the receiver member by heat and pressure to form a permanent reproduction thereon.
For control of the electrostatographic reproduction apparatus process, appropriate sensors are provided to detect the position of the dielectric support member in relation to the image forming processing stations, and the location of a receiver member in its travel path, and produce appropriate signals indicative thereof. Such signals are fed as input information to a process controller having a logic and control unit including a microprocessor, for example. Based on such signals and a suitable program for the microprocessor, the logic and control unit produces signals to control the timing operation of the various electrographic process stations for carrying out the reproduction process. The production of a program for a number of commercially available microprocessors is a conventional skill well understood in the art. The particular details of any such program would, of course, depend on the architecture of the designated microprocessor. The process control for the reproduction apparatus is limited by the particular value range of signals provided by the sensors for the process controller logic and control unit or sent to the process elements by the logic and control unit. If elements outside the normally provided process elements are substituted as replacement parts, the signal to or from such replacement parts may fall outside the particular value range for the reproduction apparatus, and will most likely cause the reproduction apparatus to fail to function properly.